$\left(x-3\right)\:\left(x+5\right)>0$

$\frac{cosx}{cosx-cos^2x}$

$\left(-\frac{4}{3}x^2+\frac{12}{5}x-6\right)\cdot\left(\frac{3}{4}x^4\right)$

$y'-\left(\sin\left(x\right)\right)y=2\sin\left(x\right)$

$x^2-64=0$

$\frac{3x^6}{4x^2}$

$\frac{\left(1-sinx\right)\left(1+sinx\right)}{cos^2x}$